1. Field of the Invention
The present invention relates to a magnetic recording device which holds a magnetic head on a magnetic disc, a photomagnetic disc or another information recording medium, and records or reads information on or from the information recording medium by the magnetic head, particularly to a support mechanism of the magnetic head.
2. Description of the Prior Art
In a conventional magnetic recording device, on a magnetic disc (hereinafter, referred to as the disc) as a magnetic recording medium, a magnetic head element (hereinafter, referred to as the magnetic head) is floated at a predetermined distance to record and reproduce information, which is known as an air-bearing floating type of magnetic disc device. In the air-bearing floating type of magnetic disc device, usually, the magnetic head is attached to a member called a slider, and the slider is operated in a system called Contact-Start-Stop (CSS). In the system, when the disc is stopped, the slider is in contact with a disc surface (i.e. a recording face of the magnetic recording medium). From when the disc starts rotating until the disc receives a fluid force resulting from the rotation to float, the slider slides on the disc surface. Also when the disc stops rotating, a rotation speed of the disc is slowed down, thereby exerting an insufficient fluid force to the slider. Then, the slide starts sliding on the disc surface.
Also, as another conventional magnetic recording device, by sliding a magnetic head or a slider in contact with a disc, a magnetic disc device performs recording/reproducing in a contact recording system. In the magnetic disc device, the magnetic head or the slider is in steady contact with the disc.
In the magnetic head and a head support mechanism for supporting the magnetic head in the conventional magnetic disc device, as disclosed in a publication of patent application laid-open No. Sho 55-22296, to a support arm for giving to a slider a pressing load onto a disc, a gimbal portion is connected, which has a pivot as a load point and a rotation spring for rotatably supporting the slider centering on the pivot in its pitching and rolling directions. To the gimbal portion, an upper face of the slider is attached.
In many cases, the gimbal portion is formed of a thin plate, and by bending or torsional-deforming the thin plate, the aforementioned rotary support is realized. Therefore, it is difficult to form the gimbal portion integrally with the support arm which is formed of a plate having a different thickness. Usually, the gimbal portion is formed of the thin plate separately from the support arm, then welded or bonded otherwise to the support arm. A publication of patent application laid-open No. Hei 8-69673 discloses an example of forming the gimbal portion by etching.
The head support mechanism in some case includes the slider, and in another case is a combination of the support arm for supporting the slider and the gimbal portion (hereinafter, referred to as the head support arm), excluding the slider. In the following description, the head support arm is indicated unless especially described. That is to say, the head support arm includes the support arm and the gimbal portion. Also in the following description, a side of the slider opposed to the disc and its opposite side are called lower and upper faces, respectively, and upstream and downstream sides of a disc rotary direction are called forward and backward portions, respectively.
In the aforementioned head support mechanism, a rotation center in a pitching direction of the slider is above a sliding face of the slider. Therefore, when the slider receives a frictional force resulting from the aforementioned sliding on the disc, a contact force of the slider with the disc becomes very large on the upstream side of the disc rotary direction, i.e. the slider falls forward to the upstream side of the disc rotary direction. In this case, because of an unstable vibration or the aforementioned locally generated very large contact force, the slider has a possibility of damaging disc and slider surfaces.
To solve the problem, a publication of patent application laid-open No. Hei 2-192082 discloses a head support mechanism constituted in such a manner even when receiving a frictional force from a disc, a slider is prevented from falling forward. A tip of an arm attached to a carriage is provided with a parallel plate structure constituted of an upper plate and a parallel lower plate to give a load. The gimbal portion is constituted of upper and lower main plate portions, and front and rear plates which connect these main plate portions. In the support mechanism, when a frictional force acts in a backward direction of the slider, the front plate of the gimbal portion is deformed to be horizontal with a disc face, while the rear plate is deformed to be vertical with the disc face. In this case, since a rotation center of the slider in a pitching direction is below a sliding face, a forward portion of the slider is lifted up, and the aforementioned falling forward does not occur.
However, in the aforementioned head support mechanism, instead of lifting up the forward portion of the slider, a backward portion of the slider is deformed to be pressed onto the disc face. There arises a distribution (load distribution) in which a load produced on the slider sliding face is increased from the forward to backward portion. In this case, since the pressing load received by the slider itself does not change, a contact force on the backward portion of the slider is increased. Then, there is a possibility that the slider and the disc are damaged.
Also, in the head support mechanism disclosed in the publication of patent application laid-open No. Hei 2-192082, the gimbal portion has a complicated structure. A disc device is not made compact. Especially, in a laminated disc type of device, the narrowing of disc intervals or the lowering of cost is not considered.